Sources and transformation pathways for dichlorodiphenyltrichloroethane (DDT) and metabolites in soils from Northwest Fujian, China

Huanfang Huang, Yuan Zhang, Wei Chen, Wenwen Chen, Dave A. Yuen, Yang Ding, Yingjie Chen, Yao Mao, Shihua Qi

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Dicofol (2,2,2-trichloro-1,1-bis-(p-chlorophenyl)ethanol) found in the environment is not only a miticide originated from commercial use, but also a metabolite of dichlorodiphenyltrichloroethane (DDT), which is often overlooked. To verify the sources and transformation pathways of DDT and related metabolites in soils, we measured p,p’-(dicofol + DBP) (sum of p,p’-dicofol and 4,4′-dichlorobenzophenone), DDT and six metabolites in soils from Northwest Fujian, China. The ratios of 1,1,1-trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane (o,p’-DDT)/1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (p,p’-DDT) and the mass balance demonstrated that p,p’-(dicofol + DBP) predominantly originated from p,p’-DDT transformation rather than from actual dicofol application. p,p’-(dicofol + DBP) accounted for 45.0% as the primary metabolites of DDT in this study, more than 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethylene (p,p’-DDE) and 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethane (p,p’-DDD), which might lead to large overestimations of the fresh DDT input by using the traditional ratio of (∑2DDD + ∑2DDE)/∑2DDT (with all o,p’- and p,p’- isomers included). In paddy fields where the conditions alternate between aerobic (dry period) and anaerobic (wet period), both p,p’-DDD and p,p’-DDE were likely to degrade to 1-chloro-2,2-bis-(p-chlorophenyl)ethylene (p,p’-DDMU), which further transformed to 2,2-bis(p-chlorophenyl)ethylene (p,p’-DDNU). Degradation of p,p’-DDMU to p,p’-DDNU mainly occurred in waterlogged paddy soils. However, p,p’-DDNU might not transform to other higher-order metabolites in aerobic surface soils. Overall, our study confirmed p,p’-(dicofol + DBP) as metabolites of p,p’-DDT, suggested DDE and DDD were parallel precursors of DDMU, and further verified the transformation pathways of DDT in surface soils.

Original languageEnglish (US)
Pages (from-to)560-570
Number of pages11
JournalEnvironmental Pollution
Volume235
DOIs
StatePublished - Apr 2018

Bibliographical note

Funding Information:
The authors are grateful to Ms Hui Li and Yan Sun for pre-treatment, and Faming Zeng for assistance in Arc-GIS. Special thanks go to Claudia Moeckel and Ekeoma Ogwo for grammar checking. This study was financially supported by the National Natural Science Foundation of China (Nos. 41073070 , 41103065 , 41473095 and 41503112 ) and Geological Survey of China (No. GZTR20080105 ).

Keywords

  • DDT
  • Dicofol
  • Metabolites
  • Surface soil
  • Transformation pathways

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